Generally, pencil sharpeners can be classified into electric pencil sharpeners and manual pencil sharpeners. Since the electric pencil sharpeners are not frequently used for sharpening pencils, they usually keep in a standby condition, which will consume powers of the batteries and is not environment protective. Conversely, hand-cranked pencil sharpeners are in a large market demand since they do not require any power supply and are compact and portable.
In prior hand-cranked pencil sharpeners, only a sharpening member is provided. When a crank is operated manually to rotate, a gearing transmits the rotation of the crank to the sharpening member so that a tip of the pencil can be sharpened. For example, there is disclosed a hand-cranked pencil sharpener that comprises a crank, an intermittent wheel, a turnplate, a positioning tube, a toolrest and a blade in Chinese Patent Application No. 90200543.X. The intermittent wheel, the turnplate, the toolrest and the blade are driven by the crank rotated by hand, so that the toolrest and the blade are reciprocated on a bump orbit having a 65° slope, as an alternative of the conventional threaded blades for sharpening pencils. In such a design, a pencil is positioned on the sharpening member and then fed into the sharpeners by gravity in theory. However, in practice, it is difficult to keep the pencil positioned on the sharpening member in position to be properly sharpened if it is not pressed by hand, since it is light and cannot resist the sharpening force applied by the blade. Therefore, the sharpening quality of the pencil sharpener cannot be ensured.
In the case that the pencil is not fed by gravity, for example, if the pencil is put into the sharpening member from a side of the pencil sharpener, the pencil needs to be held and fed by hand when the blade is rotated with the crank in the sharpening. Alternatively, a pencil clamp can be provided at an input of the sharpening member when the sharpening member is rotated by the crank, and apply a clamping force on the pencil so that the pencil is prevented from dropping and can be drawn into the sharpening member gradually by a spring in the pencil clamp. However, it is instable to hold and feed the pencil by hand, resulting that the pencil is easy to be broken off. As for the pencil clamp design, the feeding force applied by the spring is not adjustable and the pencil clamp has to be removed from the pencil sharpener before the pencil is to be sharpened. Such configurations are also not capable of ensuring the sharpening quality and make the pencil sharpener inconvenient to be used.